Drinking-induced blackouts among young adults: results from a national longitudinal study

Dual-color miniscope imaging of microvessels and neuronal activity in the hippocampus CA1 region of freely moving mice following alcohol administration

Moderate-to-heavy episodic ("binge") drinking is the most common form of alcohol consumption in the United States. Alcohol at binge drinking concentrations reduces brain artery diameter in vivo and in vitro in many species including rats, mice, and humans. Despite the critical role played by brain vessels in maintaining neuronal function, there is a shortage of methodologies to simultaneously assess neuron and blood vessel function in deep brain regions. Here, we investigate cerebrovascular responses to ethanol by choosing a deep brain region that is implicated in alcohol disruption of brain function, the hippocampal CA1, and describe the process for obtaining simultaneous imaging of pyramidal neuron activity and diameter of nearby microvessels in freely moving mice via a dual-color miniscope. Recordings of neurovascular events were performed upon intraperitoneal injection of saline versus 3 g/kg ethanol in the same mouse. In male mice, ethanol mildly increased the amplitude of calcium signals while robustly decreasing their frequency. Simultaneously, ethanol decreased microvessel diameter. In females, ethanol did not change the amplitude or frequency of calcium signals from CA1 neurons but decreased microvessel diameter. A linear regression of ethanol-induced reduction in number of active neurons and microvessel constriction revealed a positive correlation (R = 0.981) in females. Together, these data demonstrate the feasibility of simultaneously evaluating neuronal and vascular components of alcohol actions in a deep brain area in freely moving mice, as well as the sexual dimorphism of hippocampal neurovascular responses to alcohol.

A mixed-methods approach to improve the measurement of alcohol-induced blackouts: ABOM-2

BACKGROUND

Alcohol-induced blackouts describe memory loss resulting from alcohol consumption. Approximately half of college students report experiencing a blackout in their lifetime. Blackouts are associated with an increased risk for negative consequences, including serious injury. Research has documented two types of blackouts, en bloc (EB) and fragmentary (FB). However, research is limited by the lack of a validated measure that differentiates between these two forms of blackout. This study used a mixed-methods approach to improve the assessment of FB and EB among young adults. Specifically, we sought to improve the existing Alcohol-Induced Blackout Measure (ABOM), which was derived from a relatively small pool of items that did not distinguish FB from EB.

METHODS

Study 1 used three rounds of cognitive interviewing with U.S. college students (N = 31) to refine existing assessment items. Nineteen refined blackout items were retained for Study 2. Study 2 used face validity, factor analysis, item response theory, and external validation analyses to test the two-factor blackout model among U.S. heavy-drinking college students (N = 474) and to develop and validate a new blackout measure (ABOM-2).

RESULTS

Iterative factor analyses demonstrated that the items were well represented by correlated EB and FB factors, consistent with our hypothesis. External validation analyses demonstrated convergent and discriminant validity. These analyses also provided preliminary evidence for the two factors having differential predictive validity (e.g., FB correlated with enhancement drinking motives, while EB correlated with coping and conformity motives).

CONCLUSIONS

The Alcohol-Induced Blackout Measure-2 (ABOM-2) improves the measurement of blackout experiences among college students. Its use could facilitate the examination of EB and FB as differential predictors of alcohol-related outcomes in future studies.

A Longitudinal Examination of Alcohol-Related Blackouts as a Predictor of Changes in Learning, Memory, and Executive Function in Adolescents

INTRODUCTION

In adolescents, the relationship between alcohol-related blackouts (ARBs) and distinct cognitive changes lasting beyond intoxication is unclear. We examined ARBs as a predictor of persistent changes in the development of learning, memory, and executive function in participants from the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA) study.

METHODS

Descriptive analyses of the NCANDA sample (N = 831, 50.9% female, 12-21 years at baseline) identified ARB patterns within participants with an ARB history (n = 106). Latent growth curve modeling evaluated ARB-related performance changes on four neuropsychological measures across five years, excluding baseline data to reduce the magnitude of practice effects over time (n = 790). Measures included the Penn Conditional Exclusion Test (PCET), Penn Letter N-back Test (PLBT), Penn Facial Memory Test immediate (PFMT_i), and delayed (PFMT_d) recognition trials, and the Rey Complex Figure Test copy (RCFT_c), immediate recall (RCFT_i), and delayed recall (RCFT_d) trials. Multivariate models were fit for raw accuracy scores from each measure, with ARB history (i.e., presence of past-year ARBs) as the main independent variable. Age, sex, race, socioeconomic status, assessment site, and alcohol use (i.e., past-year frequency) were included as covariates. Interaction effects between ARB history and alcohol use frequency were tested.

RESULTS

By year five, 16% of participants had experienced at least one ARB (59% of whom reported > 1 ARB and 57% of whom had an ARB lasting > 1 h). After controlling for demographics and alcohol use, ARB history predicted attenuated PFMT_d performance growth at year one. Interaction effects between ARB history and alcohol use frequency predicted attenuated PFMT_d performance growth at years one and two. ARB history predicted attenuated RCFT_i and RCFT_d performance growth by year four, but not PCET or PLBT performance over time. By contrast, greater past-year alcohol use predicted attenuated PFMT_i and PFMT_d performance growth between years two and four in adolescents without an ARB history.

CONCLUSION

We found that ARBs predict distinct, lasting changes in learning and memory for visual information, with results suggesting that the developing brain is vulnerable to ARBs during adolescence and emerging adulthood.

Persistent attention-deficit/hyperactivity disorder predicts socially oriented, but not physical/physiologically oriented, alcohol problems in early adulthood

BACKGROUND

Although individuals with histories of childhood attention-deficit/hyperactivity disorder (ADHD) report more alcohol-related problems in adulthood than those without ADHD, it is unknown whether there are group differences in certain types of alcohol problems. We tested whether the nature of alcohol problems differed for individuals with and without childhood ADHD, as well as adulthood-persistent ADHD, to facilitate a personalized medicine approach for alcohol problems in this high-risk group.

METHODS

Data were drawn from a prospective, observational study. Children diagnosed with ADHD and demographically similar individuals without childhood ADHD were followed prospectively through young adulthood (N = 453; 87.6% male). ADHD symptom persistence was assessed using self-reports and parent reports. Alcohol problems and heavy drinking were assessed repeatedly from 18-30 years old to construct lifetime measures.

RESULTS

Full-sample confirmatory factor analyses identified 5 alcohol problem "types:" interpersonal problems/risky behaviors, occupational/academic impairment, impaired control/treatment seeking, tolerance/withdrawal, and drinking to blackout. Latent class analyses of items within each type yielded the best fit for 3-class solutions for all sets of items except blackout drinking, for which 2 classes emerged. Children with ADHD were more likely than those without ADHD to belong to high-risk latent classes for interpersonal problems/risky behaviors, occupational/academic problems, and impaired control (the high-risk class that indexed treatment-seeking behavior). These effects were driven by individuals whose ADHD symptoms persisted into adulthood. Few group differences emerged for tolerance/withdrawal and blackout drinking, except that individuals with only childhood ADHD (no persistence) were more likely to belong to the low-risk groups than those with adulthood-persistent ADHD and without ADHD.

CONCLUSIONS

Individuals with ADHD histories whose symptoms persist into adulthood may be more likely to experience socially oriented alcohol problems and impaired control/treatment seeking than individuals without an ADHD history and those with childhood ADHD only. Tailored alcohol prevention and treatment programs may benefit this high-risk population.

The morning after the night before: Alcohol-induced blackouts impair next day recall in sober young adults

Binge-drinking in adolescents and young adults is a widespread problem, however, an often unreported consequence of binge-drinking behaviour is an alcohol-induced memory blackout (MBO). An MBO is a transient amnesic event resulting from rapid, excessive alcohol consumption. Here, we examine the short-term impact of an alcohol-induced MBO event (testing < 20 hours after blackout) on memory performance in people who have experienced a high volume of MBOs. In addition, we aimed to test the hypothesis that people who experience a high volume of MBOs may have poorer recall than non-blackout controls in either sober or intoxicated states. Three episodic memory paradigms consisting of free recall, serial recall, and depth of encoding tasks, were conducted by a group of alcohol drinkers who had never experienced a memory blackout, and those who reported at least 9 in the preceding 12-months. Studies were completed sober and after alcohol by all participants, and sober but after blackout by the experimental group. Accuracy of recall was assessed with linear mixed effects modelling for all experiments and conditions. Recall rate both before and after alcohol consumption was similar between groups, with poorer recall after drinking alcohol by all participants in all three studies. After blackout, MBO participants showed no significant improvement from their intoxicated state in serial recall and depth of encoding tasks, but an improvement in free recall. Further analysis of these findings revealed that 10 out of 23 participants showed significantly impaired performance after blackout during free recall, extending up to 17 participants in serial recall. In general, alcohol reduced recall rate in both blackout and control participants similarly, but recall following MBO remained poor. Our evidence suggests that alcohol-induced blackouts impair memory functioning the next day, and future research should establish the duration of deficits after an acute alcohol-induced blackout episode.

Posting Post-Blackout: A Qualitative Examination of the Positive and Negative Valence of Tweets Posted after "Blackout" Drinking

Alcohol-induced memory loss (i.e., blackout) is a consequence of drinking that is both common and associated with additional negative outcomes. The goal of the present study was to use publicly available Twitter data to better understand cognitions and emotions following blackouts. Tweets containing key terms (e.g., "black out") were collected over 4 days in 2018. Using NVivo software, we coded all post-blackout Tweets for valence (positive, negative, neutral). Within each valence category, we reviewed Tweets to identify themes. Among Tweets coded with a positive valence, themes included pride in blacking out, pride in ability to function despite blackouts, blackouts as a shared social experience, and overall positive views of a drinking experience despite blackouts. Among Tweets coded with a negative valence, themes included the experience of other negative consequences on blackout nights, blackouts as unexpected/unplanned, blackouts as motivator of change, and blackout-related negative emotions. Additionally, Tweeters expressed pride in avoiding blackouts during drinking events. Findings provide insight into why not all individuals describe blackouts negatively, by analyzing specific statements made in a public forum following a blackout. Such insight may inform interventions targeting those who report this risky outcome of drinking, including those that could be delivered via social media.

Difference in Cognitive Function by First Onset Age of Alcohol Induced Blackout and Its Duration

Objective

Alcohol-induced blackout (blackout) is a typical early symptom of cognitive impairment caused by drinking. However, the first onset age of blackout or the duration after onset of blackout has not been directly compared in previous studies. The purpose of this study was to investigate the differences in cognitive function to the first start age of blackouts and their duration.

Methods

Thirty-one male subjects were included in this study. Their age at the first blackout and the duration after the onset of blackout were investigated. Neuropsychological tests were conducted to determine their attention, memory, and executive function. Subjects were divided into three groups according to their age of the first onset blackout (group O1, < 20 years; group O2, 21–39 years; and group O3, > 40 years). Subjects were also divided into three groups by duration after the onset of blackout (P1, < 10 years; P2, 10–29 years; and P3, > 30 years). We then examined differences in neurocognitive function among these groups.

Results

O1 tended to have a lower memory score than O2 (F = 3.28, p = 0.053). Significant differences were observed in attention and executive function between groups P1 and P3 (Digit Span_backward: F = 6.07, p < 0.05; visual span_forward: F = 4.19, p < 0.05; executive intelligence quotient: F = 3.55, p < 0.05).

Conclusion

Greater memory impairment was detected in subjects having an earlier age of the first blackout. The longer the duration after the onset of blackout, the more impaired their attention and executive function skills.

Event-Level Correlates of Drinking Events Characterized by Alcohol-Induced Blackouts

BACKGROUND

Prior research identifies a range of potential predictors of blackouts and suggests that blackouts increase risk for additional negative consequences. However, these studies are based on epidemiological work that allows us to draw conclusions about groups of people but not within-person processes. The present study examined within-person, event-level correlates of blackouts.

METHODS

Ninety-six heavy drinking college students (52% female) completed 28 days of daily reports of alcohol use and consequences, including blackouts. Thirty-three participants reported 56 blackouts. Hierarchical linear modeling compared morning reports of drinking events on which participants did versus did not report a blackout, controlling for total drinks at the event.

RESULTS

Blackout likelihood increased as a function of total drinks consumed and of crossing thresholds for heavy episodic drinking (4+/5+ drinks for women/men) and high-intensity drinking (8+/10+). Participants reported a higher total number of additional negative consequences on blackout events. Specific consequences that were more likely included embarrassing oneself and hangover. Blackouts were associated with morning ratings of less positive mood and a less favorable drinking event. Motives for drinking and simultaneous use of marijuana were not associated with blackouts.

CONCLUSIONS

Event-level findings of this study document that events leading to alcohol-induced memory loss are associated with other adverse experiences relative to drinking events that do not result in blackout, and offer potentially motivational levers for preventive interventions.

Women's Experiences of Impairment and Incapacitation During Alcohol/Drug-Related Sexual Assaults: Toward a Survivor-Informed Approach to Measurement

Researchers have categorized level of impact of drinking during alcohol/substance facilitated sexual assaults as unimpaired (perceived no effect of drinking), impaired (conscious, but impacted by substance use), or incapacitated (unconscious due to substance use). However, researchers have not always agreed on what constitutes these categories, and no qualitative research has been done to date to explore those discrepancies. Such work is needed in order to listen to survivors' voices, using their perspectives and experiences to develop trauma-informed practices specific to survivors of alcohol-involved assaults. The current study sought to shed light on impaired/incapacitated sexual assault experiences presenting 141 qualitative written responses of women who were drinking and/or using substances at the time of their assault. Results showed that while some responses aligned with previous researcher-defined quantitative impaired/incapacitated categories, most responses coded could be considered both impaired and incapacitated, or neither of these categories. Implications for further research, particularly qualitative work, are discussed specifically challenging previous research on impaired/incapacitated sexual assault experiences.

Alcohol-induced blackouts at age 20 predict the incidence, maintenance and severity of alcohol dependence at age 25: a prospective study in a sample of young Swiss men

BACKGROUND AND AIMS

Alcohol-induced blackout (AIB) is a common alcohol-related adverse event occurring during teenage years. Although research provides evidence that AIB predicts acute negative consequences, less is known about the associations of AIB with chronic consequences, such as alcohol dependence (AD). This study estimated the associations between an experience of AIB at age 20 and the incidence, maintenance and severity of AD at age 25 among Swiss men.

DESIGN

Prospective cohort study with 5.5 years separating baseline and follow-up.

SETTING

Switzerland.

PARTICIPANTS

Swiss male drinkers (n = 5469, age 20 at baseline) drawn from the Cohort Study on Substance Use Risk Factors (C-SURF).

MEASUREMENTS

Self-report questionnaires assessing AIB, AD, alcohol (drinking volume, binge drinking), cigarette and cannabis use, several risk factors (sensation-seeking, family history of problematic alcohol use, age of first alcohol intoxication) and socio-demographic variables.

FINDINGS

Generalized estimating equation models with and without adjustment for risk factors, including alcohol use and socio-demographics, showed that AIB at age 20 significantly predicted the incidence of AD at age 25 in men without AD at age 20 [odds ratio (OR) = 2.52, 95% confidence interval (CI), unadjusted = 2.04, 3.11, P < 0.001; fully adjusted, OR = 1.47, 95% CI = 1.13, 1.91, P = 0.004], maintenance of AD in men with AD at age 20 (unadjusted, OR = 1.82, 95% CI = 1.12, 2.95, P = 0.015; fully adjusted, OR = 1.66, 95% CI = 1.00, 2.76, P = 0.048] and AD severity [unadjusted incidence rate ratio (IRR) = 1.89, 95% CI = 1.69, 2.11, P < 0.001; fully adjusted, IRR = 1.20, 95% CI = 1.10, 1.31, P < 0.001].

CONCLUSIONS

Among Swiss men, alcohol-induced blackout at age 20 predicts the development, maintenance and severity of alcohol dependence at age 25.

"Can't Wait to Blackout Tonight": An Analysis of the Motives to Drink to Blackout Expressed on Twitter

BACKGROUND

Alcohol-related blackouts are associated with a range of negative consequences and are common among social drinkers. Discussing alcohol use on social networking platforms (e.g., Twitter) is common and related to higher alcohol consumption levels. Due to the widespread nature of alcohol-related social networking posts and alcohol-related blackouts, we examined the content of alcohol-related blackouts posts/"Tweets" on Twitter, with a focus on intentions to blackout and specific motivations for blacking out.

METHODS

A set of Tweets containing "blackout," "blackout," "blacking out," "blacked out," or "blacks out" were collected from April 26, 2018, and April 29, 2018. Using NVivo software, we coded all preblackout Tweets (i.e., before the blackout experience) for intentions and motives to blackout.

RESULTS

Most Tweets that we collected expressed an intention to blackout and these intentions ranged in strength (i.e., will blackout vs. might blackout). With respect to specific motives for blacking out, celebration motives were identified. For example, Tweets addressed blacking out to celebrate one's birthday, someone else's birthday, a school or work accomplishment, a sports win, during a vacation, or a holiday. Another endorsed motive for blacking out was loss or coping motives. For example, the Tweets commented on blacking out to deal with stress or a bad day.

CONCLUSION

Our findings suggest that Twitter users express intentions to blackout due to celebration or coping reasons. Given the consequences associated with blackout drinking, future research should consider the link between blackout intentions, blackout motives, and alcohol-related harm.

Correlates of Breath Alcohol Concentration Among Driving Under the Influence Program Clients in Southern California

Understanding factors correlated with breath alcohol concentration (BrAC) at time of arrest for driving under the influence (DUI) may lead to informed rehabilitation programs. This study describes correlations between BrAC at time of arrest and sociodemographic, mental, and physical health, and alcohol-related characteristics among clients in a large California DUI Program. Client reported data ( n = 17,282) were collected at an intake from 2009 to 2014. BrACs ranged from 0.083% to 0.390%, with an average of 0.159% ( SD = 0.051), almost twice the legal limit in the state. Approximately 10.6% of the variance in BrAC was explained by 11 significant correlates. Two sociodemographic factors (age and race/ethnicity) as well as several alcohol-related characteristics were related to higher BrAC levels, whereas comorbid mental and physical health factors played less of a role. Factors associated with BrAC are complex and warrant further investigation to identify causality and inform future interventions.

Alcohol-induced blackouts, subjective intoxication, and motivation to decrease drinking: Prospective examination of the transition out of college

OBJECTIVE

We prospectively examined whether subjective intoxication serves as a risk factor for experiencing alcohol-induced blackouts. We then examined whether subjective intoxication and/or blackouts predicted motivation to decrease their drinking, and whether this motivation to change would promote future changes in drinking behavior.

METHOD

Participants (N=1854, 62.1% female, 53.2% Caucasian, M_age=21.8) were recruited the summer prior to matriculating into a large, public university to complete a 6-year longitudinal study. Self-reported motivation to decrease their drinking behavior, their frequency of blackouts, quantity of alcohol consumption, and subjective intoxication (i.e., feeling drunk) were assessed annually during the transition out of college (Years 4-6).

RESULTS

In a cross-lagged model, subjective intoxication (i.e., feeling drunk) prospectively predicted experiencing blackouts (p<0.001). Controlling for both objective (e.g., quantity) and subjective intoxication, blackouts at Year 4 predicted greater motivation to decrease drinking behavior at Year 5 (p<0.01), but this motivation did not predict less quantity of alcohol use by Year 6 (p=0.076).

CONCLUSIONS

Subjective intoxication is a robust predictor of blackouts across time. Additionally, blackouts are modest, developmentally-limited predictors of motivation to change drinking behavior, but blackouts do not predict future behavior change.

A longitudinal event-level investigation of alcohol intoxication, alcohol-related blackouts, childhood sexual abuse, and sexual victimization among college students

Sexual assault is a troubling epidemic that plagues college campuses across the United States, and is often proceeded by drinking by the perpetrator and/or victim. The goal of this study was to examine the effect of level of intoxication, history of alcohol-related blackouts, and childhood sexual abuse (CSA) on the likelihood of being a victim or perpetrator of coercive sexual activities. Participants (N = 2,244) were part of a 6-year longitudinal study which explored alcohol use and associated behavioral risks during college. A subsample (N = 1,423) completed 30 days of daily diary surveys across four years of college. Participants provided daily reports of their alcohol consumption, sexual coercion perpetration, and sexual coercion victimization. Using hierarchical linear models, results indicated that increases in daily estimated blood alcohol concentration (eBAC) were associated with a greater likelihood of being a victim and a perpetrator of sexual coercion. In addition, main effects of CSA and history of blackouts predicted a greater likelihood of being coerced into sexual activity, but blackouts were not associated with being a perpetrator. A significant interaction between blackouts and event-level eBAC indicated that individuals with a history of blackouts had a greater likelihood of sexual coercion victimization relative to those without prior blackouts. Finally, having a history of blackouts and CSA was predictive of a lower likelihood of being a perpetrator of sexual coercion at higher eBACs relative to those without a history of blackouts. Thus, prevention efforts should integrate the impact of blackouts and CSA on sexual coercion victimization and perpetration. (PsycINFO Database Record

Predictors of Patterns of Alcohol-Related Blackouts Over Time in Youth From the Collaborative Study of the Genetics of Alcoholism: The Roles of Genetics and Cannabis

OBJECTIVE

Alcohol-related blackouts (ARBs) are anterograde amnesias related to heavy alcohol intake seen in about 50% of drinkers. Although a major determinant of ARBs relates to blood alcohol concentrations, additional contributions come from genetic vulnerabilities and possible impacts of cannabis use disorders (CUDs). We evaluated relationships of genetics and cannabis use to latent class trajectories of ARBs in 829 subjects from the Collaborative Study of the Genetics of Alcoholism (COGA).

METHOD

The number of ARBs experienced every 2 years from subjects with average ages of 18 to 25 were entered into a latent class growth analysis in Mplus, and resulting class membership was evaluated in light of baseline characteristics, including CUDs. Correlations of number of ARBs across assessments were also compared for sibling pairs versus unrelated subjects.

RESULTS

Latent class growth analysis identified ARB-based Classes 1 (consistent low = 42.5%), 2 (moderate low = 28.3%), 3 (moderate high = 22.9%), and 4 (consistent high = 6.3%). A multinomial logistic regression analysis within latent class growth analysis revealed that baseline CUDs related most closely to Classes 3 and 4. The number of ARBs across time correlated .23 for sibling pairs and -.10 for unrelated subjects.

CONCLUSIONS

Baseline CUDs related to the most severe latent ARB course over time, even when considered along with other trajectory predictors, including baseline alcohol use disorders and maximum number of drinks. Data indicated significant roles for genetic factors for alcohol use disorder patterns over time. Future research is needed to improve understanding of how cannabis adds to the ARB risk and to find genes that contribute to risks for ARBs among drinkers.

Blackouts among male and female youth seeking emergency department care

BACKGROUND

Alcohol-related blackouts are a common consequence of heavy drinking, and these blackouts pose risk for injury and other adverse health outcomes.

OBJECTIVE

To examine the prevalence and correlates of blackouts among underage drinkers.

METHODS

Youth (ages 14-20) presenting to a suburban Emergency Department (ED) completed screening surveys. Among those reporting past-year alcohol consumption, we examined past 3-month blackouts in relation to: background characteristics (e.g., demographics, fraternity/sorority involvement), substance use, sexual risk behaviors and incapacitated sexual assault (unaware/unable to consent due to alcohol/drugs), forced sexual assault, positive depression screening, and reason for ED visit (injury vs. medical).

RESULTS

In total, 2,300 past-year drinkers participated: 58% female, 75% Caucasian, and mean age = 18.4. Regarding past 3-month blackouts, 72.7% reported none, 19.3% reported monthly or less, and 8% reported monthly or more. Multivariate cumulative logit regression indicated that blackout frequency was positively associated with: college involvement in Greek life, alcohol use severity, prescription drug misuse, marijuana, screening positive for depression, incapacitated sexual assault, and a gender by alcohol use severity interaction.

CONCLUSION

With one-quarter of this clinical sample reporting recent blackouts, as well as the association between blackout frequency and health risk behaviors and other outcomes, findings underscore the need for programs focusing on substance use, depression, and preventing sexual assault. Interventions should also address poly-substance use and drinking motives. Although findings highlight how college students in Greek life may be at high risk for blackouts, many participants not in college also reported blackouts, suggesting that interventions in other settings are also needed.

Latent growth classes of alcohol-related blackouts over the first 2 years of college

Alcohol-related blackouts are common among college student drinkers. The present study extends prior work by examining latent growth classes of blackouts and several predictors of class membership. Participants (N = 709 college drinkers) completed a baseline survey at college entry and biweekly online assessments throughout freshman and sophomore years. Results revealed 5 latent growth class trajectories, reflecting varying experiences of blackouts at the beginning of college and differential change in blackouts over time. The largest class represented a relatively low-risk group (low decrease; 47.3%) characterized by endorsement of no or very low likelihood of blackouts, and decreasing likelihood of blackouts over time. Another decreasing risk group (high decrease; 11.1%) initially reported a high proportion of blackouts and had the steepest decrease in blackout risk over time. A small percentage showed consistently high likelihood of blackouts over time (high stable; 4.1%). The remaining 2 groups were distinguished by relatively moderate (moderate stable; 14.9%) and lower (low stable; 22.6%) likelihood of blackouts, which remained stable over time. Comparisons between classes revealed that students with greater perceived peer drinking, perceived peer approval of drinking, and enhancement motives upon entry to college tended to be in higher risk groups with consistent experiences of blackouts over time, whereas blackout likelihood decreased over time for students with greater conformity motives. Findings suggest that precollege preventive interventions may be strengthened by considering not only factors related to current risk for blackouts and other alcohol-related consequences, but also those factors related to persistence of these behaviors over time. (PsycINFO Database Record

Alcohol-Induced Blackouts: A Review of Recent Clinical Research with Practical Implications and Recommendations for Future Studies

BACKGROUND

Alcohol-induced blackouts, or memory loss for all or portions of events that occurred during a drinking episode, are reported by approximately 50% of drinkers and are associated with a wide range of negative consequences, including injury and death. As such, identifying the factors that contribute to and result from alcohol-induced blackouts is critical in developing effective prevention programs. Here, we provide an updated review (2010 to 2015) of clinical research focused on alcohol-induced blackouts, outline practical and clinical implications, and provide recommendations for future research.

METHODS

A comprehensive, systematic literature review was conducted to examine all articles published between January 2010 through August 2015 that focused on vulnerabilities, consequences, and possible mechanisms for alcohol-induced blackouts.

RESULTS

Twenty-six studies reported on alcohol-induced blackouts. Fifteen studies examined prevalence and/or predictors of alcohol-induced blackouts. Six publications described the consequences of alcohol-induced blackouts, and 5 studies explored potential cognitive and neurobiological mechanisms underlying alcohol-induced blackouts.

CONCLUSIONS

Recent research on alcohol-induced blackouts suggests that individual differences, not just alcohol consumption, increase the likelihood of experiencing an alcohol-induced blackout, and the consequences of alcohol-induced blackouts extend beyond the consequences related to the drinking episode to include psychiatric symptoms and neurobiological abnormalities. Prospective studies and a standardized assessment of alcohol-induced blackouts are needed to fully characterize factors associated with alcohol-induced blackouts and to improve prevention strategies.

Early Onset Drinking Predicts Greater Level But Not Growth of Alcohol-Induced Blackouts Beyond the Effect of Binge Drinking During Emerging Adulthood

BACKGROUND

Early onset drinking is associated with later heavy drinking and related consequences. Early drinking onset and binge drinking are also independently associated with blackouts, which are periods of amnesia for events during a drinking episode. The objective of this study was to examine how early onset drinking relates to changes in the frequency of experiencing blackouts across 3 years controlling for year-specific binge drinking.

METHODS

Participants (N = 1,145; 67.9% female) from a 6-year, longitudinal study are included in these analyses. Measures of self-reported age at drinking onset included ages at first drink, first high, and first drunk, which were used to create a latent early onset drinking factor. Frequency of binge drinking and blackouts were assessed annually during Years 4 to 6.

RESULTS

Overall, 69.2% of participants reported experiencing blackouts. After controlling for year-specific binge drinking, a growth curve model indicated that early onset drinkers reported more frequent blackouts at Year 4. There were, however, no significant effects of acceleration or deceleration in the frequency of blackouts across the 3 years. Early onset drinkers continued to experience more frequent blackouts compared with those who initiated alcohol use later, despite decreases in binge drinking over time.

CONCLUSIONS

Early onset drinkers reported more frequent blackouts across all 3 years, indicating that early alcohol initiation predisposes those individuals to continue to experience more frequent blackouts, despite a decrease in their binge drinking. This may be due to various factors, such as altered hippocampal development and functioning resulting from early alcohol exposure.

Alcohol-Induced Blackouts and Other Negative Outcomes During the Transition Out of College

OBJECTIVE

There is considerable debate about the prospective association between alcohol-dependence symptoms and alcohol-related blackouts. The goal of this study was to examine the associations among alcohol-dependence symptoms, blackouts, and social and emotional consequences during the transition out of college.

METHOD

Participants (N = 829; 66% female) were part of a 6-year longitudinal study designed to explore alcohol use and risky behaviors during and after college. Data for these analyses were from Years 4 and 5 of data collection, which most closely corresponded to the transition out of college. Using cross-lagged models, we tested the prospective associations of alcohol-dependence symptoms, blackout frequency, and social and emotional consequences.

RESULTS

Alcohol-dependence symptoms in Year 4 predicted increased frequency of blackouts and social and emotional consequences during the subsequent year. Blackouts during Year 4 also significantly predicted increased alcohol-related social and emotional consequences, but not dependence symptoms, in Year 5.

CONCLUSIONS

Although blackouts do not predict the development of alcohol-dependence symptoms, they increase the risk for less severe alcohol-related consequences during the transition out of college. This may result from the cognitive reconciliation of negative behaviors that occur during these episodes of amnesia.

Expert testimony in sexual assault cases: Alcohol intoxication and memory

At court-martial tribunals in the United States military, cases involving alcohol facilitated sexual assault often pivot on the alleged victim's level of intoxication or impairment and ability to consent to the sexual act. These cases frequently arise following a night of partying and heavy drinking among a group of friends and acquaintances, military and civilian. The determination of whether a sexual act was consensual may rest on estimates of the alleged victim's blood alcohol concentration and related behavioral indicia of impairment. Expert testimony may be presented by the prosecution and/or the defense, from forensic toxicologists and psychiatrists or psychologists regarding the potential involvement of alcohol and its impact on the participants relevant to the charges at court-martial. A review of the state of the science is offered to bring such testimony into perspective. Appellate cases illustrate that the experts' testimony may sometimes elucidate, sometimes obfuscate, and sometimes exceed professional expertise and invade the province of the factfinder.

Alcohol-induced blackouts and maternal family history of problematic alcohol use

BACKGROUND

Consequences of heavy drinking include alcohol-induced blackouts, which are periods of amnesia for all or part of a drinking event. One risk factor for blackouts is family history of problematic alcohol use (FH+); however, research rarely distinguishes maternal from paternal FH+. The objective of this study was to examine whether maternal or paternal FH+ better predicts likelihood of experiencing blackouts than a general measure of overall FH+, and whether gender moderates this association.

METHOD

Participants (N=1164; 65.4% are female) were first-time college freshmen (age range=17-19) who participated in a 6-year, 10-assessment, longitudinal study in the United States. Alcohol-induced blackouts, the dependent measure, were dichotomized (yes/no) based on endorsement of memory problems after drinking using a single item during Years 4-6. FH+, captured at baseline, was coded if participants self-reported that their mother, father, or any of their four grandparents were a possible or definite problem drinker.

RESULTS

Overall, 773 (66.4%) participants reported experiencing blackouts during Years 4-6. Women were more likely to report blackouts than men; however, compared with women with a maternal FH+, men with a maternal FH+ were more than twice as likely to report blackouts.

DISCUSSION

Men appear to be more susceptible than women to the effects of a maternal FH+. Genetic and environmental explanations for this finding are discussed. In sum, these findings are an important step toward understanding a significant yet understudied negative consequence of heavy alcohol use.

Latent trajectory classes for alcohol-related blackouts from age 15 to 19 in ALSPAC

BACKGROUND

Alcohol-related blackouts (ARBs) are reported by ~50% of drinkers. While much is known about the prevalence of ARBs in young adults and their cross-sectional correlates, there are few prospective studies regarding their trajectories over time during mid-adolescence. This paper reports latent trajectory classes of ARBs between age 15 and 19, along with predictors of those patterns.

METHODS

Latent class growth analysis (LCGA) was used to evaluate the pattern of occurrence of ARBs across 4 time points for 1,402 drinking adolescents from the Avon Longitudinal Study of Parents and Children (ALSPAC). Multinomial regression analyses evaluated age-15 demography, substance-related items, externalizing characteristics, and estimated peer substance use as predictors of latent class membership.

RESULTS

ARBs were reported at age 15 in 30% and at age 19 in 74% of these subjects. Four latent trajectory classes were identified: Class 1 (5.1%) reported no blackouts; for Class 2 (29.5%), ARBs rapidly increased with age; for Class 3 (44.9%), blackouts slowly increased; and for Class 4 (20.5%), ARBs were consistently reported. Using Class 2 (rapid increasers) as the reference, predictors of class membership included female sex, higher drinking quantities, smoking, externalizing characteristics, and estimated peer substance involvement (pseudo R(2)  = 0.22).

CONCLUSIONS

ARBs were common and repetitive in these young subjects, and predictors of their trajectories over time involved multiple domains representing diverse characteristics.

Alcohol-induced blackout as a criminal defense or mitigating factor: an evidence-based review and admissibility as scientific evidence

Alcohol-related amnesia--alcohol blackout--is a common claim of criminal defendants. The generally held belief is that during an alcohol blackout, other cognitive functioning is severely impaired or absent. The presentation of alcohol blackout as scientific evidence in court requires that the science meets legal reliability standards (Frye, FRE702/Daubert). To determine whether "alcohol blackout" meets these standards, an evidence-based analysis of published scientific studies was conducted. A total of 26 empirical studies were identified including nine in which an alcohol blackout was induced and directly observed. No objective or scientific method to verify the presence of an alcoholic blackout while it is occurring or to confirm its presence retrospectively was identified. Only short-term memory is impaired and other cognitive functions--planning, attention, and social skills--are not impaired. Alcoholic blackouts would not appear to meet standards for scientific evidence and should not be admissible.

Evaluating amnesia for criminal behavior: a guide to remember

This article provides a guide that is important to remember in evaluating a criminal defendant's amnesia claim. Important concepts to understand regarding memory formation, memory systems, proposed causes of amnesia, reasons why amnesia claims may be true or false, and important strategies to implement as part of the evaluation process are reviewed. Structured assessment approaches are critical components of amnesia evaluations and generally require detailed questioning, review of collateral records, medical and neurologic workups, psychological testing, neuropsychological testing, and specific malingering assessments.

Alcohol-induced blackout

For a long time, alcohol was thought to exert a general depressant effect on the central nervous system (CNS). However, currently the consensus is that specific regions of the brain are selectively vulnerable to the acute effects of alcohol. An alcohol-induced blackout is the classic example; the subject is temporarily unable to form new long-term memories while relatively maintaining other skills such as talking or even driving. A recent study showed that alcohol can cause retrograde memory impairment, that is, blackouts due to retrieval impairments as well as those due to deficits in encoding. Alcoholic blackouts may be complete (en bloc) or partial (fragmentary) depending on severity of memory impairment. In fragmentary blackouts, cueing often aids recall. Memory impairment during acute intoxication involves dysfunction of episodic memory, a type of memory encoded with spatial and social context. Recent studies have shown that there are multiple memory systems supported by discrete brain regions, and the acute effects of alcohol on learning and memory may result from alteration of the hippocampus and related structures on a cellular level. A rapid increase in blood alcohol concentration (BAC) is most consistently associated with the likelihood of a blackout. However, not all subjects experience blackouts, implying that genetic factors play a role in determining CNS vulnerability to the effects of alcohol. This factor may predispose an individual to alcoholism, as altered memory function during intoxication may affect an individual’s alcohol expectancy; one may perceive positive aspects of intoxication while unintentionally ignoring the negative aspects. Extensive research on memory and learning as well as findings related to the acute effects of alcohol on the brain may elucidate the mechanisms and impact associated with the alcohol-induced blackout.

Social inequality and racial discrimination: risk factors for health disparities in children of color

A child's sense of control over life and health outcomes as well as perceptions of the world as fair, equal, and just are significantly influenced by his or her social experiences and environment. Unfortunately, the social environment for many children of color includes personal and family experiences of racial discrimination that foster perceptions of powerlessness, inequality, and injustice. In turn, these perceptions may influence child health outcomes and disparities by affecting biological functioning (eg, cardiovascular and immune function) and the quality of the parent-child relationship and promoting psychological distress (eg, self-efficacy, depression, anger) that can be associated with risk-taking and unhealthy behaviors. In this article we review existing theoretical models and empirical studies of the impact of racial discrimination on the health and development of children of color in the United States. On the basis of this literature, a conceptual model of exposure to racial discrimination as a chronic stressor and a risk factor for poor health outcomes and child health disparities is presented.

Subjective responses to alcohol prime event-specific alcohol consumption and predict blackouts and hangover

OBJECTIVE

Individual differences in subjective response to alcohol and the occurrence of blackouts and hangover are associated with the development of alcohol-use disorders. As such, subjective responses to alcohol, blackouts, and hangover may share a biological vulnerability to excessive alcohol consumption. The purpose of the current study was to examine subjective responses to alcohol as predictors of estimated blood alcohol concentration (BAC), blackouts, and hangover for a single heavy drinking event.

METHOD

Data were collected on 150 (50% female) college students at a large, public university who reported consuming alcohol during their 21st birthday celebration. Using semi-structured interviews and self-report measures, subjective responses to alcohol (at midpoint of a 21 st birthday celebration) were examined as predictors of final estimated BAC, blackouts, and hangover.

RESULTS

Stimulant effects reported for the midpoint of the drinking event predicted final estimated BAC. Both stimulant and sedative alcohol effects directly predicted blackouts during the drinking event and the occurrence of a hangover. Neither stimulant nor sedative effects were mediated by final estimated BAC.

CONCLUSIONS

Retrospective reports of subjective responses to alcohol were associated with the level of intoxication, blackouts, and hangover during a heavy drinking event. Findings therefore suggest the utility of incorporating subjective responses to alcohol into event-specific interventions that are designed to reduce or prevent heavy episodic drinking.

Alcohol-induced retrograde memory impairment in rats: prevention by caffeine

RATIONALE

Ethanol and caffeine are two of the most widely consumed drugs in the world, often used in the same setting. Animal models may help to understand the conditions under which incidental memories formed just before ethanol intoxication might be lost or become difficult to retrieve.

OBJECTIVES

Ethanol-induced retrograde amnesia was investigated using a new odor-recognition test.

MATERIALS AND METHODS

Rats thoroughly explored a wood bead taken from the cage of another rat, and habituated to this novel odor (N1) over three trials. Immediately following habituation, rats received saline, 25 mg/kg pentylenetetrazol (a seizure-producing agent known to cause retrograde amnesia) to validate the test, 1.0 g/kg ethanol, or 3.0 g/kg ethanol. The next day, they were presented again with N1 and also a bead from a new rat's cage (N2).

RESULTS

Rats receiving saline or the lower dose of ethanol showed overnight memory for N1, indicated by preferential exploration of N2 over N1. Rats receiving pentylenetetrazol or the higher dose of ethanol appeared not to remember N1, in that they showed equal exploration of N1 and N2. Caffeine (5 mg/kg), delivered either 1 h after the higher dose of ethanol or 20 min prior to habituation to N1, negated ethanol-induced impairment of memory for N1. A combination of a phosphodiesterase-5 inhibitor and an adenosine A(2A) antagonist, mimicking two major mechanisms of action of caffeine, likewise prevented the memory impairment, though either drug alone had no such effect. Binge alcohol can induce retrograde, caffeine-reversible disruption of social odor memory storage or recall.

The Association of Alcohol-Induced Blackouts and Grayouts to Blood Alcohol Concentrations

The primary aim of this study was to investigate the association between measured blood alcohol concentration (BAC) and the presence and degree of amnesia (no amnesia, grayout, or blackout) in actively drinking subjects. A secondary aim was to determine potential factors other than BAC that contribute to the alcohol-induced memory loss. An interview questionnaire was administered to subjects regarding a recent alcohol associated arrest with a documented BAC greater than 0.08 g/dL for either public intoxication, driving under the influence, or under age drinking was administered. Demographic variables collected included drinking history, family history of alcoholism, presence of previous alcohol-related memory loss during a drinking episode, and drinking behavior during the episode. Memory of the drinking episode was evaluated to determine if either an alcohol-induced grayout (partial anterograde amnesia) or blackout (complete anterograde amnesia) occurred. Differences in (1) mean total number of drinks ingested before arrest, (2) gulping of drinks, and (3) BAC at arrest were found for those having blackouts compared with no amnesia; while differences in drinking more than planned were found between the no amnesia and grayout groups. A strong linear relationship between BAC and predicted probability of memory loss, particularly for blackouts was obvious. This finding clinically concludes that subjects with BAC of 310 g/dL or greater have a 0.50 or greater probability of having an alcoholic blackout.

Alcohol-induced memory impairment in trace fear conditioning: a hippocampus-specific effect

It has been hypothesized that the amnesic effects of alcohol are through selective disruption of hippocampal function. Delay and trace fear conditioning are useful paradigms to investigate hippocampal-dependent and independent forms of memory. With delay fear conditioning, learning of explicit cues does not depend on normal hippocampal function, whereas learning explicit cues in trace fear conditioning does. In both delay and trace fear conditioning, the hippocampus is involved in learning to contextual cues, but it may not be entirely necessary. The present study investigates the effects of alcohol on the acquisition of delay and trace fear conditioning in mice, using freezing as a measure of learning. Male C57BL/6J mice were injected with 0.8 or 1.6 g/kg of 20% v/v alcohol and were immediately exposed to eight tone-footshock pairings in which the conditional stimulus (CS) either coterminated with a footshock unconditional stimulus (US) (delay conditioning) or was separated from the footshock by a 30-s trace interval (trace conditioning). During trace, but not delay fear conditioning, 0.8 g/kg alcohol impaired learning to a tone CS. This dose also impaired context-dependent learning in both procedures (although only slightly for trace fear conditioning). The 1.6 g/kg alcohol exerted a nonselective impairment on learning. The impairment by alcohol of learning to a tone CS when it is hippocampus-dependent, but not when it is hippocampus-independent provides further support for the hypothesis that alcohol exerts a selective effect on hippocampus-dependent learning.

Prevalence and correlates of alcohol-induced blackouts among college students: results of an e-mail survey

The authors conducted an e-mail survey of 772 college students to learn more about their experiences with blackouts. Approximately half (51%) of those who had ever consumed alcohol reported they had experienced a blackout at some point in their lives, and 40% had experienced 1 in the year before the survey. Among those who drank in the 2 weeks before the survey, nearly 1 in 10 (9.4%) had experienced a blackout during that period. Many later learned that, during the blackout, they had vandalized property, driven an automobile, had sexual intercourse, or engaged in other risky behaviors. Experiencing 3 or more blackouts was associated with a variety of other experiences, including heavier drinking, lower grades, an earlier age of drinking onset, and having others express concerns about their drinking. The female students who reported blackouts during the 2 weeks before the survey drank far less than male students did during this time period, supporting the use of gender-specific definitions of risky drinking.

Parental alcoholism as a risk factor for DSM-IV-defined alcohol abuse and dependence in American women: the protective benefits of dyadic cohesion in marital communication

Important trends in research over the past decade indicate that women are as greatly affected by familial alcoholism as are men. Although it is increasingly recognized that the adverse drinking outcomes predicted for adult children of alcoholics (COAs) are not inevitable, and only a small percentage develop alcohol dependence or grow up to be alcoholic, relatively little knowledge exists regarding moderating factors that reduce their vulnerability. This study identifies a multiple mediator latent structural model of the intergenerational transmission of risk for DSM-IV-assessed alcohol abuse and dependence among women COAs in adulthood. The effects of both parental alcoholism and family environment are estimated at three time points spanning 10 years across 5-year intervals (1984, 1989, and 1994) using data from a subsample of 4,449 women in the National Longitudinal Survey of Youth (NLSY). Dyadic cohesion in marital communication (greater marital cohesion, harmony, and less verbal disagreement, discord, and conflict) is a proposed moderating factor that may operate in adulthood to lower the risk of female COAs developing alcohol abuse and dependence. Maximum likelihood standardized estimates of the effects of alcohol mediators measured over time indicate that direct parental effects for adverse outcomes decline when COAs are in their late 20s and early 30s. Indirect parental effects through environmental influences dramatically increase the risk of abuse and dependence among COAs at this time if they have one or more alcoholic siblings, especially an alcoholic sister. Dyadic cohesion and positive interpersonal communication patterns were found to moderate effectively the relationship that existed among parental alcoholism, environmental influences, and adverse alcohol consequences. COAs with satisfactory marital communication also evidenced higher levels of intimacy with their partners, perceived the division of housework to be fairer, shared more responsibilities and burdens of the household, and had less conflict over critical domestic issues than other women COAs. The protective benefits of a good marriage against the risks of alcoholism remained when applied to younger and older subjects, across diverse backgrounds, and after adjusting for other factors such as employment status.

Alcohol dependence in adult children of alcoholics: longitudinal evidence of early risk

This study investigates familial alcoholism effects and the comparative probability of risk for alcohol dependence in adult children of alcoholics (ACAs) with a control group of non-ACAs. A cohort of 12,686 young adults from the National Longitudinal Survey of Youth (NLSY) is examined over a five-year period and conventional and lineal intergenerational models of alcoholism transmission are assessed. The results of multivariate logistic regression analyses indicate that the risk is relatively greater for male ACAs; sons of alcoholics drink significantly more heavily, experience problems earlier, and develop alcohol dependence more extensively than female ACAs or non-ACAs of either gender. The extent of dependence found in subjects with a lineal history of alcoholism on the father's side of the family, as well as heavy drinking, cigarette smoking and drinking onset in adolescence should be considered as critical predisposing factors of high risk for dependence at later ages. These observations corroborate clinical studies and support a growing body of biopsychosocial research literature.

Resilience to drinking vulnerability in women with alcoholic parents: the moderating effects of dyadic cohesion in marital communication

Data from a subsample of women (N = 4,235) in two waves of the National Longitudinal Surveys of Youth (NLSY) are used to examine the relationship between parental alcoholism and alcohol use in adult life. Dyadic cohesion in marital communication (frequency of interaction and agreement on substantive issues that affect couples) is investigated as a resilience factor that could potentially mitigate adverse drinking outcomes in adult children of alcoholics (ACAs). A moderated mediation model is estimated using a Two-Stage Least Squares (2SLS) regression analysis. The results indicated that an imputed transmission of risk for drinking vulnerability in women ACAs, controlling for nonACA status, was effectively moderated by positive dyadic interaction.